A Systematic Analytical Study of certain North 
American Convallariaceae, considered in regard to 
their Origin through Discontinuous Variation . 1 
BY 
R. RUGGLES GATES, Ph.D., F.L.S., 
Sometime Lecturer in the University of London and Professor in the University of California, 
T HE following is a precis of the main points in the original paper, the 
full publication of which is reserved until after the War : 
The work is a systematic treatment of the Convallariaceae of North 
America which aims primarily to consider their relationships and phylogeny 
from the point of view of the mutationist. By analysis of the characters of 
the various species and genera, it is shown that many of the specific and 
generic differences are such as may have arisen through marked discon¬ 
tinuous changes. Indeed, many of the differences cannot be reasonably 
interpreted as the result of the gradual accumulation of smaller differences 
*—the older Darwinian view of evolution. The paper is, therefore, an 
application to systematic work of the mutationist conceptions gained from 
experimentation. Its aim is to show how specific differences can be 
analytically treated in terms of definite and marked variations. It appears 
that apparently great external changes may be the result of a single germinal 
alteration, and that related species have often not been gradually differen¬ 
tiated, but have arisen by definite steps and probably in many cases without 
any aid from Natural Selection. 
Many difficulties naturally arise in connexion with this or any other 
method of explanation, and a number of these difficulties are discussed in 
the paper. 
Since the North American Polygonatums have been very much con¬ 
fused and are not yet well understood, an account of this genus is published 
elsewhere. 2 The genus Trillium and its relatives, and the extensive litera¬ 
ture on the variations of Trillium , are also treated in another publication. 3 
1 A synopsis of this paper was presented before the Royal Society of Canada, at Ottawa, in 
May, 1917, by Dr. A. H. Maekay, Superintendent of Education for Nova Scotia. 
2 Gates, R. R. : A Revision of the Genus Polygonaium in North America. Bull. Torr. Bot. 
Club, vol. xliv, 1917, pp. 117-26, Pis. 1 V-VI. 
3 A Systematic Study of the North American Genus Trillium , its Variability, and its Relation 
to Paris and Medeola. Annals, Missouri Bot. Garden, vol. iv, pp. 43-92, Pis. VI-V 1 II, Map. 
[Annals of Botany, Vol. XXXII. No. CXXVI. April, 1918.] 
